Electrical devices, especially portable products, tend to become smaller, thinner, and lighter. An electrical device usually comprises different circuit boards therein which need to be electrically connected to each other. In order to improve the utilization rate of space inside the electrical device, different circuit boards are usually applied with a board-to-board (BTB) electrical connector for electrical connection.
The BTB electrical connector is an electrical connector assembly. In general, the electrical connector assembly comprises a plug connector and a receptacle connector corresponding to the plug connector. A plurality of terminals is arranged on the receptacle connector, and a plurality of columnar terminals is arranged on the plug connector. When the plug connector is mated with the receptacle connector, the columnar terminals are mated with the terminals for the signal connection between two printed circuit boards.